|
Size: 184
Comment: -9
|
Size: 1973
Comment: slightly better sed
|
| Deletions are marked like this. | Additions are marked like this. |
| Line 1: | Line 1: |
| Wow! Cool design, great info! olives Very cool! http://blcmd.vox.com/library/post/canned-pumpkin-pie-filling-recipes.html frozen felt, http://salinasii.vox.com/tags/ carrots, Shrug. | <<Anchor(faq19)>> == How can I split a file into line ranges, e.g. lines 1-10, 11-20, 21-30? == Some Unix systems provide the {{{split}}} utility for this purpose: {{{#!highlight bash split --lines 10 --numeric-suffixes input.txt output- }}} For more flexibility you can use {{{sed}}}. The {{{sed}}} command can print e.g. the line number range 1-10: {{{#!highlight bash sed 10q # Print lines 1-10 and then quit. sed '1,5D; 10q' # Print just lines 6-10 by filtering the first 5 then quitting after 10. }}} The `D` command stops {{{sed}}} from printing each line. This could alternatively have been done by passing sed the `-n` option and printing lines with the `p` command rather than deleting them with `D`. It makes no difference. We can now use this to print an arbitrary range of a file (specified by line number): {{{#!highlight bash # POSIX shell file=/etc/passwd range=10 cur=1 last=$(wc -l < "$file") # count number of lines chunk=1 while [ $cur -lt $last ] do endofchunk=$(($cur + $range - 1)) sed -n -e "$cur,${endofchunk}p" -e "${endofchunk}q" "$file" > chunk.$(printf %04d $chunk) chunk=$(($chunk + 1)) cur=$(($cur + $range)) done }}} The previous example uses POSIX [[ArithmeticExpression|arithmetic]], which older [[BourneShell|Bourne shells]] do not have. In that case the following example should be used instead: {{{#!highlight bash # legacy Bourne shell; assume no printf either file=/etc/passwd range=10 cur=1 last=`wc -l < "$file"` # count number of lines chunk=1 while test $cur -lt $last do endofchunk=`expr $cur + $range - 1` sed -n -e "$cur,${endofchunk}p" -e "${endofchunk}q" "$file" > chunk.$chunk chunk=`expr $chunk + 1` cur=`expr $cur + $range` done }}} Awk can also be used to produce a more or less equivalent result: {{{#!highlight bash awk -v range=10 '{print > FILENAME "." (int((NR -1)/ range)+1)}' file }}} ---- CategoryShell |
How can I split a file into line ranges, e.g. lines 1-10, 11-20, 21-30?
Some Unix systems provide the split utility for this purpose:
1 split --lines 10 --numeric-suffixes input.txt output-
For more flexibility you can use sed. The sed command can print e.g. the line number range 1-10:
The D command stops sed from printing each line. This could alternatively have been done by passing sed the -n option and printing lines with the p command rather than deleting them with D. It makes no difference.
We can now use this to print an arbitrary range of a file (specified by line number):
1 # POSIX shell
2 file=/etc/passwd
3 range=10
4 cur=1
5 last=$(wc -l < "$file") # count number of lines
6 chunk=1
7 while [ $cur -lt $last ]
8 do
9 endofchunk=$(($cur + $range - 1))
10 sed -n -e "$cur,${endofchunk}p" -e "${endofchunk}q" "$file" > chunk.$(printf %04d $chunk)
11 chunk=$(($chunk + 1))
12 cur=$(($cur + $range))
13 done
The previous example uses POSIX arithmetic, which older Bourne shells do not have. In that case the following example should be used instead:
1 # legacy Bourne shell; assume no printf either
2 file=/etc/passwd
3 range=10
4 cur=1
5 last=`wc -l < "$file"` # count number of lines
6 chunk=1
7 while test $cur -lt $last
8 do
9 endofchunk=`expr $cur + $range - 1`
10 sed -n -e "$cur,${endofchunk}p" -e "${endofchunk}q" "$file" > chunk.$chunk
11 chunk=`expr $chunk + 1`
12 cur=`expr $cur + $range`
13 done
Awk can also be used to produce a more or less equivalent result:
1 awk -v range=10 '{print > FILENAME "." (int((NR -1)/ range)+1)}' file